The purpose of this research is to develop an immunoassay to human lead- binding protein (PbBP) and determine its clinical utility. Lead is a pervasive pollutant. Because it is indestructible, much of the lead mined over the last 5,000 years remains in the environment and its continued use in manufactured goods makes it likely that human exposure will persist. The detrimental health effects of lead exposure have been well documented. The lowering of the cut-off for medical intervention to 10 ug/dl combined with data suggesting that cognition and neurobehavior are adversely affected at these low exposures, makes it clear that methods for assessing the consequences of low-level exposures is crucial for maintaining human health standards. One means of measuring the effects of low-level exposure is through biological markers. The aim of the research proposed here is to assess PbBP as a biomarker for lead exposure. PbBPs are proteins with high affinity and specificity for binding lead. In a rat model, PbBP was excreted into the urine in response to exposure to low levels of lead in drinking water. It follows that the human analogue may respond similarly and thus be a useful biomarker for low-level lead exposure. PROPOSED COMMERCIAL APPLICATIONS: Successful completion of the work proposed will permit development of an immunometric assay for measuring PbBP in body fluids. A test for evaluating the consequences of low-level lead exposure is expected to positively impact the health care of populations at risk for lead poisoning.